Can I delete a sales order pick transaction if the lines have already been shipped or canceled?

If the shipment lines are in Released to Warehouse status, then the pick slip report has been printed for the pickers to complete their picks. It's assumed that the materials have been physically moved to the staging subinventory.

For this reason, picking lines are kept when a sales order is canceled. To remove this transaction, you have two choices. You can either pick the full quantity and the material moves to the staging subinventory, but isn't attached to the sales orders. Or, if the full material isn't physically moved, you can pick 0 for the picking lines from the Confirm Picks Slips page to delete the transaction.

Note: You must use the Confirm Pick Slip page (instead of the Manage Pending Transactions page) to delete a pick pending transaction.